ABC News(SEOUL) -- During the first inter-Korean summit in April, North Korean leader Kim Jong Un brought a specialty dish of Pyongyang cold noodles for his South Korean counterparts to taste.

Last month, when South Korean president Moon Jae-in visited Pyongyang for the third inter-Korean summit, his welcome lunch banquet was held at a popular cold noodle restaurant in Pyongyang called Okryugwan.

Curiosity about the simple dish, called Naeng-myon in Korean, has skyrocketed sales in South Korea since the summits.

Pyongyang-style cold noodles have been around since the division of Korea, but they have never been so popular before.

"Cold noodle was considered a summer delicacy in South Korea, but this year it was different," Park Sung-jun, who has run and been the main chef at a Pyongyang cold noodle restaurant called Nam Po Myun Oak for 30 years said.

This year's noodle sales were off the charts for the eatery.

"We sold around 700 cold noodles a day since the April inter-Korean summit, which is twice the usual sales," he said.

The most notable characteristic of Pyongyang-style noodles is chilled beef broth, which has a bland, savory flavor. The noodles also break more easily compared to the usual cold noodles sold in Seoul because of their greater buckwheat content.

A North Korean defector who once worked at the famous Okryugwan in Pyongyang opened his North Korean food restaurant Dongmu Bapsang in 2015. There, he cooks Pyongyang-style cold noodles that he learned from Okryugwan back in 1973, when he was a soldier in charge of cooking for North Korean generals.

"My Pyongyang cold noodle follows the Okryugwan restaurant style during the late North Korean leader Kim Jong Il era," Yoon Jong-chol, who defected from North Korea 18 years ago, proudly said. "Now that North Korea has a new leader, the Pyongyang cold noodles at Okryugwan seems to have found a new look to suit the new generation."

Another North Korean defector Cho Su-ae stopped by the restaurant to taste Pyongyang style cold noodles and told ABC News, "The cold noodles at Dongmu Bapsang reminds me of the taste from the North."

Other North Korean dishes are benefiting from renewed interest, as well. Demand for Pyongyang-style dumplings and a boiled beef platter called Eobok Jaengban have also increased in South Korea.

Eobok Jaengban used to be street food back in the old days, when food was bountiful in North Korea. But after famine swept through the communist country, it became a cuisine that could only be enjoyed by the wealthy.

"Eobok Jaengban includes parts of beef that people usually don’t eat, such as beef lung, liver, tongue and brisket, which is why it was enjoyed by merchants in the market place," Kim Ihn Bok, who runs a North Korean food restaurant Seogwanmyeonog, said. "But now even these parts have become scarce in Pyongyang."